Function A block of PHP code that has a name and it has a property that it is reusable it can be executed from as many different points in a PHP Program as required. Also known as a method (if it is inside a class). Most Joomla code is inside functions/methods.
Language Override An optional file that allows the site administrator to override any language string in core Joomla or in an extension (other than installing a new language). There are two override files, one for the front-end and one for the administrative back-end.
FOSS Acronym for Free or open-source software. Software, like Joomla, that is available to use, copy, study, and change in any way without charge. FOSS software typically uses a special software license, such as GPL, that requires any derivative works to also be free.
